The present invention relates generally to anthropomorphic test dummies of the type utilized for aviation and automotive crash research and, in particular, to a system for assessing soft tissue damage to such dummies.
Simulated crashes have been used to test the safety of vehicles and their components. Such tests may involve the use of dummies simulating human beings or other devices selected to simulate particular parts of the human body. In these tests, it is desired to obtain a measure of the damage that would be sustained by a human being in similar circumstances. In the testing of windshields in particular, the damage is generally measured from the acceleration pulses and the facial lacerations sustained by the head of an anthropomorphic dummy or similar simulator. A medical interpretation is then placed on these measurements to estimate the degree of injury that a human being would be expected to suffer in similar circumstances. Thus, there are two distinct but dependent steps: measurement and interpretation.
In the case of head acceleration, the measurement can be made with some precision utilizing accelerometers. The interpretation is less precise, but attempts have been made by use of various criteria, such as the Gadd Severity Index and the Head Injury Criterion, to relate acceleration measurements to injury in medical terms. In the case of facial laceration, the situation is much less precise. Both the measurement of laceration on simulations of skin and on subcutaneous tissue and their interpretation in terms of the expected severity of injury have been a matter of skilled subjective judgment.
Attempts have been made to produce numerical ranking scales of the severity of general facial laceration. The Corning Scale is one of the most comprehensive and widely used. It uses a skin and subcutaneous tissue simulation consisting of two chamois leathers covering an underlying layer of rubber. Many other ranking scales used are derived from the Coming Scale or generally correspond to it.
Another known laceration scale is the Triplex Laceration Index which was developed for the quantitative assessment of the severity of lacerations in the two layers of chamois leather and the subcutaneous tissue simulation used in laceration investigations. This method uses a simple mathematical formula to relate the severity of laceration to the number, length and depth of cuts in the tissue simulations. The formula gives an excellent correlation with the existing scale used by Corning and was devised using the data on various levels of laceration obtained on an impact rig resembling the Coming Skull Impactor.
In approximately 92% of frontal impacts, where car drivers wearing seat belts strike their heads against steering wheels, soft tissue injuries result. Approximately 57% of these are single facial injuries. The lifesaving benefits of seat belts are now beyond question. However, the use of seat belts (along with air bags) has increased the need to understand the biomechanics of other, less severe traumas, such as facial laceration.
Test dummies are a very important tool for use in evaluating the crashworthiness of vehicles. In fact, such dummies have become the stars of television, radio and print media advertisements. In the field of automotive crash test research, various types of dummies have been developed to represent a range of sizes of adults and children associated with the human population.
A full line of anthropomorphic test dummies is available from First Technology Safety Systems, Inc. of Plymouth, Mich. Included in the line are a BioSID side impact test dummy, Hybrid III test dummies in ninety-fifth percentlie male, fifth percentile female, and fiftieth percentile configurations, a Side Impact model 572-SID test dummy, a Hybrid II fiftieth percentlie test dummy, six-year-old and three-year-old child test dummies, a three-year-old airbag test dummy, a model CAMI-II infant test dummy, and VIP model test dummies in ninety-fifth and fifth percentlie configurations.
The BioSID test dummy utilizes Hybrid III head, neck and leg assemblies and six ribs which are an adaptation of the Hybrid III design constructed from vascomax steel and oriented 90.degree. so that the faces of the ribs are turned toward the area of impact. The BioSID pelvis is capable of accepting a pubic and sacrum load cell. The Hybrid III ninety-fifth percentile male and the Hybrid III fifth percentile female test dummies include a three- or six-axis neck transducer, submarining indicator pelvis, chest displacement transducer, tibia-femur displacement transducers and mounts for head, chest and pelvis accelerometers. The Hybrid III fiftieth percentile test dummy eliminates the submarining indicator pelvis used on the other Hybrid III dummies and meets the specifications for the FMVSS 208 option specified in 49 CFR Part 572 Subpart E.
The Side Impact model 572-SID test dummy meets the specifications for the FMVSS 208 standard specified in 49 CFR Part 572 Subpart F utilizing Hybrid II head, neck and lower leg assemblies with upper and lower torso assemblies designed for side impacts. The Hybrid II fiftieth percentile test dummy meets the specifications for the FMVSS 208 standard specified in 49 CFR Part 572 Subpart B including mounts for head, chest and pelvis accelerometers.
The six-year-old child test dummy meets the specifications for the proposed FMVSS 208 standard and includes mounts for head, chest and pelvis accelerometers. The three-year-old test dummy meets the specifications for the FMVSS 213 standard specified in 49 CFR Part 572 Subpart C and includes mounts for head and chest accelerometers.
The three-year-old child airbag test dummy is of an experimental sit/stand construction. The infant test dummy meets the specifications for the FMVSS 213 standard specified in 49 CFR Part 572 Subpart D. and includes mounts for head, chest and pelvis accelerometers. The VIP test dummies include mounts in the head and chest for accelerometers.
The test dummies should simulate the response of a human body to crash forces with as much accuracy as possible. In addition to including sensors for measuring load and acceleration, the dummies are covered by an artificial "skin" molded from a polyurethane material for measuring laceration injuries. The current practice of testing dummy headforms for laceration injuries is to fasten a chamois or leather covering over a headform and evaluate the damage using a known laceration scale.